Low Frequency Noise in Nanoscale pMOSFETs with Strain Induced Mobility Enhancement and Dynamic Body Biases

Abstract

Local strain effect on low frequency noise (LFN) of pMOSFETs with gate length down to 60 nm was investigated in this paper. Novel and interesting results were identified from the pMOSFETs adopting embedded SiGe (e-SiGe) in source/drain for uni-axial compressive stress. This local compressive strain can realize significant mobility enhancement and desired current boost in nanoscale pMOSFETs. However, the dramatic increase of LFN emerges as a penalty traded off with mobility enhancement. The escalated LFN may become a critical killer to analog and RF circuits. Forward body biases (FBB) can improve the effective mobility (mu(eff)) and reduce LFN attributed to reduced normal field (E(eff)). However, the benefit from FBB becomes insignificant in strained pMOSFETs with sub-100 nm gate length.